Polyamidoxime and imidazole polymers

ABSTRACT

PROCESS FOR THE PREPARATION OF POLYMERS WHICH COMPRISES REACTING AT TEMPERATURES OF FROM ABOUT 0* TO ABOUT 250*C. AN AROMATIC DIAMINE WITH A BIS(HYDROXAMOYL HALIDE)-BIS(CARBOXYLIC ACID) OR A DERIVATIVE THEREOF TO FORM A POLYAMIDOXIME, WHICH MAY THEN BE SUBJECTED TO RING CLOSING CONDITIONS TIO FORM POLY(BISBENZIMIDAZOBENZOPHENANTHROLINE) (BBB) TYPE POLYMERS. FORMATION OF THE POLYAMIDOXIME IS PREFERABLY CONDUCTED IN THE PRESENCE OF A SOLVENT, WHICH MAY OR MAY NOT ALSO FUNCTION AS AN ACID-ACCEPTOR; IF NOT, THEN PREFERABLY ALSO IN THE PRESENCE OF AN ACID-ACCEPTOR. THE PREFERRED ACID-ACCETPRS ARE THOSE WHICH ARE INSOLUBLE IN THE REACTION MIXTURE-MOST PREFERABLY MELAMINE. THE RING CLOSURE MAY BE CONDUCTED IN THE PRESENCE OF A CATALYST AT TEMPERATURES OF FROM ABOUT 0* TO ABOUT 250*C. OR BY REACTION WITH AN AROMATIC SULFONYL HALIDE AT TEMPERATURES OF FROM ABOUT 0* TO ABOUT 90*C. REACTIVE AMINE OR HYDROXAMOYL HALIDE TERMINAL GROUPS OF THE POLYAMIDOXIMES OR BBB TYPE POLYMERS MAY BE REACTED WITH OTHER COMPOUNDS OR POLYMERS WHICH CONTAINS GROUPS REACTIVE THEREWITH IN ORDER TO FURTHER EXTEND THE POLYMER CHAINS. IN A PREFERRED PRIOR STEP, AROMATIC BIS(HYDROXAMOYL HALIDE)BIS(CARBOXYLIC ACID) REACTANTS ARE MADE BY THE REACTION OF DIALKYL-DICABROXY AROMATIC PRECURSORS WITH, E.G., NITROSYL HALIDE. NOVEL POLYAMIDOXIMES.

United States Patent 3,806,494 POLYAMIDOXIME AND IMIDAZOLE POLYMERS CarlN. Zellner, New Hope, Pa., assignor to Celanese Corporation, New York,N.Y. No Drawing. Continuation-impart of application Ser. No.

85,750, Oct. 30, 1970. This application Aug. 4, 1972,

Ser. No. 277,957

Int. Cl. C08g 20/32 US. Cl. 260-78 TF 6 Claims ABSTRACT OF THEDISCLOSURE Process for the preparation of polymers which comprisesreacting at temperatures of from about 0' to about 250 C. an aromaticdiamine with a bis(hydroxamoyl halide)-bis(carboxylic acid) or aderivative thereof to form a polyamidoxime, which may then be subjectedto ring closing conditions to formpoly(bisbenzimidazobenzophenanthroline) (BBB) type polymers. Formationof the polyamidoxime is preferably conducted in the presence of asolvent, which may or may not also func tion as an acid-acceptor; ifnot, then preferably also in the presence of an acid-acceptor. Thepreferred acid-acceptors are those which are insoluble in the reactionmixture-most preferably melamine. The ring closure may be conducted inthe presence of a catalyst at temperatures of from about 0 to about 250C. or by reaction with an aromatic sulfonyl halide at temperatures offrom about 0 to about 90 C. Reactive amine or hydroxamoyl halideterminal groups of the polyamidoximes or BBB type polymers may bereacted with other compounds or polymers which contain groups reactivetherewith in order to further extend the polymer chains. In a preferredprior step, aromatic bis(hydroxa.moyl halide)- bis(carboxylic acid)reactants are made by the reaction of dialkyl-dicarboxy aromaticprecursors with, e.g., nitrosyl halide. Novel polyamidoximes.

CROSS REFERENCE TO RELATED APPLICATION This is a continuation-in-part ofUS. application Ser. No. 85,750, filed Oct. 30, 1970.

This invention relates to a novel process for the preparation ofpolyamidoximes and to poly(aroylenebenzimidazoles) or, moreparticularly, to poly(benzimidazobenzophenanthroline) (BBB) typepolymers produced therefrom.

Polyamidoximes are useful as chelating agents for sequesteringpolyvalent metal ions in plating baths, polluted streams, etc. Thepolymers are also useful as catalyst carriers and as ion-exchangeresins. The polymers may be formed into fibers, films, molded articles,etc. Instead of undergoing ring closure to form the BBB type polymers ofthis invention, the polyamidoximes may be hydrolyzed to high performancepolyamides by reaction with, e.g., dilute hydrochloric acid, or theiroxime groups may be hydrogenated under appropriate conditions to aminegroups to form polyamines, which are also useful as chelating agents.The polyamines may be reacted with polyepoxides to form epoxy resins andmolded articles, or they may be crosslinked with dicarboxylic acids toform polyamide resins of interesting and varied properties.

The BBB polymers of this invention generally are useful for applicationswhere high performance polymers are required. For example, in aerospaceapplications where retention of strength at elevated temperatures andflame retardancy are required, the BBB polymers of this invention areespecially outstanding. Heretofore, Nomex polyamide type resins havebeen used in coveralls, etc., worn by pilots and race car drivers toprotect against injuries from fires resulting from crashes, etc.Unfortunately, Nomex garments are not as non-flammable as desired. Inaddition, wearers of these garments have complained that they areclammy, especially when worn in a closed cockpit. BBB type polymers aremuch less flammable than Nomex resins. Garments made from BBB typepolymers are not clammy, especially when the fabric in the garment iswoven from staple, which fabric has the feel of cotton.

Heretofore, BBB type polymers have been made by the reaction ofdiaminobenzidine with a tetracarboxylic acid or a derivative thereof.Overall this process is undesirable because it is expensive and alsobecause of toxicity problems. The diaminobenzidine is difiicult tosynthesize and difiicult to purify, thereby resulting in a veryexpensive starting material. This compound is also highly toxic. Theother starting material is usually a tetracarboxynaphthalene, which isalso relatively expensive because it is not, as of now, an article ofcommerce. Another drawback to the prior art process is thatrelatively'high temperatures are required, e.g., temperatures in therange of about 390 C.

One or more of the foregoing and other adverse effects of the prior artprocess are overcome by the novel process of the present invention.

Generally, the process of the present invention comprises reacting anaromatic diamine with a bis(hydroxamoyl halide)-'bis(carboxylic acid) toform the polyamidoxime, which may then be subjected to ring closingconditions to form the BBB type polymers of this invention.

Illustrative of the aromatic diamines which may be used in the presentinvention are those which may be depicted by the following generalformula:

C H -CsH -C6H RC H,, wherein R is as defined below, and the like. Y maybe substituted with groups which do not detrimentally interfere with thereaction.

lllustrative subcategories of the diamines which may be used are:

(I) Compounds of the general formula (H) Compounds of the generalformula HI I--CuH O|HiI IH (III) Compounds of the general formulaIllustrative of particular aromatic diamines which may be used in theprocess of this invention are the following:

m-phenylene diamine p-phenylene diamine o-phenylene diamine1,4-naphthalene diamine 1,5-naphthalene diamine 1,6-naphthalene diamine1,7-naphthalene diamine 1,8-naphthalene diamine 2,3-naphthalene diamine2,6-naphthalene diamine 2,7-naphthalene diamine1,4-diaminoZ-methyl-naphthalene 1,4-diamino-anthracene 2,6-diaminoanthracene 9, 1 O-diamino-anthracene 9 1 O-diamino-phenanthrene2,2-diamino-biphenyl 2,4'-diamino-biphenyl 3,3-diamino-biphenyl3,4'-diamino-bipheny1 4,4'-diamino-biphenyl4,4'-diamino-2,2'-dimethyl-biphenyl 1,1-bis(4-aminophenyl) cyclohexanebis (4-aminophenyl)dimethyl silane bis(4aminophenyl) diethyl silanebis(4-aminophenyl) diphenyl silane bis(4-aminophenyl) aminebis(4-aminophenyl) ether, i.e., 4,4'-diamino diphenyl etherbis(4-aminophenyl) thioether 2,2-bis(4-aminophenyl) propanebis(4-arninophenyl) sulfone bis(4-aminophenyl) sulfoxidebis(4-aminophenyl) ketone bis(4-aminophenyl) methane.

By the term aromatic diamine" is meant a compound in which the two aminogroups are each attached to an aromatic ring, not necessarily bothattached to the same ring, however. Generally, any aromatic diaminecontaining up to about 30 carbon atoms can be used in the presentinvention. Preferably, the diamine contains up to about 20 carbon atoms,most preferably up to about 15 carbon atoms. The most preferred diaminesare benzidine and oxydianiline.

Bis(hydroxamoyl halide)-bis(carboxylic acids) which may be used in thisinvention contain aromatic nuclei and may be, e.g., to the chlorides,bromides or iodides. The chlorides and bromides are generally preferred.The compounds are illustrated by the following formula:

wherein X is halogen or OR", SR" (R" is alkyl of up to 4 carbon atoms)or OC H and R is a tetravalent carbocyclic (rings formed only of carbon)aromatic radical or an aromatic radical having a bridge group joiningtwo carbocyclic aromatic radicals as described above and having a totalof 4 valence positions whether R is a bridged carbocyclic aromaticradical or a plain carbocyclic aromatic radical, and wherein saidvalence positions are attached to the carbocyclic ring. The bridgegroups are divalent in character and may be selected from the following:

and the like.

In the R radical its valences are so positioned that a carbohydroxamoylhalide group (R" is alkyl of up to 4 carbon atoms),

-s Oz-CHg-@ or -s Or-CH group.

Illustrative of the aromatic groups represented by R 7 8 Hooc coon coonoi o or or NOH 01 Cm- \NOH i non NOH r N 011 nooc c oon 0 BF Br\ /Br orn00 coon CH g 10 HON NOH NOH \COOH 1 H000 CH 00 on B 01 NOH 01 r c- -cO=NOH 5 non H. NOH

HON OH; NOH C( \CI H000 000R 01 coon nooc Cl NOH NOH o- -o -o o-- R c H01 HON NO Illustrative compounds containing the R radical are COOH H000the following: c1 c1 coon coon c -o 0 Br (I) /Br HON NOH C L K non NOHCl coon coon CI 11000 ooon 1? HON NOH /C S -C HON NOH 40 Cl coon coon ClCOOH COOH \C S- 0 ll HON N011 HON l) NOH nooc coon G1 I O1 nooc coon IIa c -o HON NOH HON O NOE H000 COOH H000 CODE 01 0 Cl B g C- c (1- OH:-CH2 -0 HON N OH HON NOH E000 COOH Generally, equimolar quantities ofthe reactants are used to form the polymers of this invention. However,it C- -CH2-CH O is possible to terminate the polymer chains with eitherhydroxamoyl halide groups or amino groups merely by utilizing in thereaction an excess of the reactant containooon COOH c1 01 mg either ofthose groups. To obtam relatively high intrinsic viscosity polymer, itis generally preferred that OH the excess not exceed about 5 molepercent. HON N When the polymer is terminated by hydroxamoyl 6 halidegroups, they may be reacted with compounds or polymers containing atleast one group, preferably two groups, which is (are) reactivetherewith under the con- HOOC 000E ditions of the reaction. Such groupsmay be, for example, 01 amines or phenoxides.

c Q When an excess of the diamine is used, the excess will function asan acid-acceptor. Excess diamine may also function as chain-stoppers, orend-blocking units, the terminal amine groups of which may serve asreactive groups through which the chain may be further extended byreaction with other compounds containing at least one group, preferablytwo groups, which is (are) reactive with the amine groups under thereaction conditions. Such groups and compounds are, for example,hydroxamoyl halide; isocyanate; halogen, e.g., chlorine and bromine;epoxide; acid chlorides, e.g., adipoyl chloride; carboxy, e.g., adipicacid, tetracarboxy-naphthalene; amine (condensation reaction); SO' Clphosgene (to form a urea linkage or to form isocyanate groups dependingon reaction conditions, which latter groups may be converted to urethanelinkages by reaction with polyols); hydrazine (to form semicarbazides);phosgenated diols (aliphatic or aromatic bis-chlorocarbonates [to formurethane linkages1).

Of course, it will be obvious to one skilled in the art that mixedpolymers may be produced by polymerizing more than one of either or eachof the two reactants. These mixed polymers may be either random oralternating and may be formed from using mixtures of diiferent speciesof either or both reactants, or they may be block polymers, which may beformed by reacting an amineterminated polymer of relatively lowmolecular weight which has itself been formed from a diamine orbis(hydroxamoyl halide)-bis(carboxylic acid) which is different fromthat used to form the first polymer. The relatively low molecular weightpolymers may instead be substantially the same except for one beingamine-terminated and the other hydroxamoyl halide terminated, andpossible differences in molecular weight and configuration.

In addition to polymers having various mixed polyamidoxime repeatingunits, polymers containing repeating units of other types of polymerssuch as polyesters, polyamides, and the like may also be prepared. Thesepolymers may be prepared by reacting, for example, an amine-terminatedpolyester with a hydroxamoyl halide terminated polymer of relatively lowmolecular weight which has itself been formed from a diamine orbis(hydroxamoyl halide)-bis(carboxylic acid) which is different fromthat used in the first polymer. Amine-terminated polyesters may beprepared for example, by utilizing a relatively low molecular weightacid terminated polyester polymer (prepared by well-known methods) andthen reacting the resulting polymer with a large excess of diamine. Thepreparation of amine-terminated polyamides is likewise well known. Ingeneral, then, the amine-terminated polymers can be prepared by carryingout a polymerization reaction and then endcapping the resulting polymerwith an amine using standard methods. Similarly hydroxamoyl halideterminated or endcapping polymers such as polyesters may be prepared andfurther reacted with aromatic diamines to form the compositions of thisinvention.

Cyclization of the polyamidoxime polymers may be accomplished before orafter linking in the manner just described. If cyclization is to beperformed before linking, the terminal amino groups may need protection,e.g., by acetylation, before cyclization is conducted. Aftercyclization, the protected groups are reconverted to amine groups byhydrolysis before linking.

Although the two reactants could be directly contacted together,especially when one or both are liquids or when the reaction temperatureis high enough to melt one or both, it is preferable to conduct thereaction in the presence of a solvent. The solvent may be inert or mayfunction as an acid-acceptor to remove the by-product hydrogen halideformed during the reaction.

Illustrative of the inert solvents which may be used are N acetonitrile;nitrated solvents, e.g., nitromethane and nitrobenzene; chlorinatedsolvents, e.g., methylene chloride, chloroform, carbon tetrachloride,ethylene chloride, and chlorobenzene; the ethers, e.g.,tetrahydrofurane, diethyl ether, and dioxane; the esters, e.g., amylacetate; the lactones, e.g., butyrolactone; ketones, e.g.,cyclopentanone, cyclohexanone; acetic acid; polyphosphoric acid andcrmols. Cyclohexanone and polyphosphoric acid are preferred.

If an inert solvent has been used, it is desirable to add to the mixturean acid-acceptor such as a tertiary amine, e.g., trialkylamines such astrimethylamine, triethylamine, and the like triethylene diamine; 1,3dimethylamino butane; heterocyclic amines such as pyridine, picolines,lutidines; or an alkali metal or alkaline earth metal hydroxide,bicarbonate, carbonate, or alkanoate (up to 4 carbon atoms), e.g.,sodium hydroxide, sodium carbonate, sodium bicarbonate, potassiumacetate, etc.

Particularly useful acid-acceptors are those insoluble in the reactionmixture, e.g., melamine, benzoguanamine, dicyanamide, insolubleguanidine derivatives, insoluble basic ion-exchange resins. Preferredare melamine and benzoguanamine. Of course, mixtures of theacidacceptors may be used. The aforementioned acid-acceptors may be usedin conjunction with the following solvents which also function asacid-acceptors.

Illustrative of the solvents which also function as acidacceptors aredimethylacetamide (DMAc), dimethylformamide (DMF), pyrrolidone, and itsalkylated derivatives, e.g., N-methyl-pyrrolidone, dimethyl sulfoxide(DMSO), hexamethylphosphoramide, dialkylanilines, e.g., dimethylanilineand diethylaniline, and the like, DMAc is preferred.

In place of a single solvent in the reaction mixture, there may be usedmixed solvent systems containing either or both types of solvents.

In order to avoid undesirable side reactions, it is preferable to useeither an acid-acceptor which is insoluble in the reaction mixture,preferably melamine, or to use a soluble amine but ensure that itsinstantaneous concentration in the reaction mixture is relatively low,e.g., lower than 0.01 molar concentration-for example, by slowly andcontinuously adding the acid-acceptor or by incrementally adding smallportions.

The reaction of the bis(hydroxamoyl halide)-bis(carboxylic acid) withthe aromatic diamine is generally exothermic and may be conducted atautogenous temperature, or it may be conducted at a constant temperatureby the application of the required cooling or heating conditions. Thereaction may be conducted at temperatures of from about 0 to about 250C., preferably about 0 to about 100 C.

The closing of the ring to actually form the imidazole polymers may beaccomplished by the appropriate thermal conditions, e.g., by heating theamidoxime polymer to a temperature in the range of about 0 to 250 C.,preferably in the presence of a catalyst, especially an acidic catalystsuch as silica gel, silica-alumina, sulfonated polystyrene ion-exchangeresins, and polyphosphoric acid. Polyphosphoric acid is the preferredcatalyst.

Ring closure may also be accomplished by the reaction of the amidoximepolymer with sulfonyl halide, such as benzene sulfonyl chloride,naphthalene sulfonyl chloride, toluene sulfonyl chloride, methanesulfonyl chloride, or other ring closing reagents under appropriateconditions, e.g., about 0 C. to about C. or higher, preferably about 5C. The aromatic sulfonyl halides are preferred, especially toluenesulfonyl chloride.

The polyamidoximes prepared according to the instant invention, haverecurring units of the following formula:

r H i coon NOH valent in character and may be selected from thefollowing:

and the like.

In the R radical, its valences are so positioned that a carbohydroxamoylhalide group and a carboxyl group are attached together through a chainof two or three carbon atoms of the R radical (the three carbon linkageis preferred), and the remaining carbohydroxamoyl halide and carboxygroups are similarly linked together, although not necessarily throughthe same two or three carbon atoms of R. Illustrative R groups havepreviously been described. It is preferred that R contains up to 18carbon atoms (most preferably about carbon atoms). R is preferably C Hmost preferably with the 3 valences in the 1, 4, 5, 8-positions. In theabove formula Y is C H C H Preferred among the amidoximes are thosewherein Y is selected from The most preferred polyamidoxime has thefollowing formula:

OOH COOH In this formula R has been described for the generallydescribed amidoxime polymers. Y is aderivative of the Y described forthe polyamidoxime polymers but is a tetravalent radical with its 4valences so positioned that one set of two valences from adjacent carbonatoms links those carbon atoms to the two respective nitrogen atoms.

Relative to the imidazole polymers, Y is selected from s z, 10 4 u e, ers s e 3- s s, wherein R is as defined below and the like. Y may besubstituted with groups which do not detrimentally interfere withreaction. In the above formula R may be and the like.

In the above formula, Y is C H C H 14 a-, C6H4' e 4- s 4 s 4 and thelike. R may be or the like.

The aromatic diamines are either readily available or easily prepared bymethods which are well known to those skilled in the art. For example,benzidine may be prepared by the palladium-catalyzed hydrogenation inalkaline medium of nitrobenzene to form hydrazobenzene, which is thenrearranged in the presence of, e.g., hydrochloric acid to form thedesired product.

The bis(hydroxamoyl halide)-bis(carboxylic acid), the other reactant inthe novel process of this invention, may be prepared by any of theroutes which suggest themselves to one skilled in the art. For example,it is known that aldehyde groups in an appropriate aliphatic or aromaticdialdehyde may be reacted with hydroxylamine to form the correspondingbisoxime, which in turn may be reacted with halogen to form abis(hydroxamoyl halide). Another method of preparing the bis(hydroxamoylhalides) is to start with the appropriate dialkyl-dicarboxy aromaticprecursor and react it with nitrosyl halide, preferably in the presenceof additional halogen, to form the bis(hydroxamoylhalide)-bis(carboxylic acids). Other reagents which may be used in placeof the nitrosyl halide per se are a combination of nitric acid andhydrohalic acid, or a combination of nitric oxide (NO) and halogen.

The dialkyl-dicarboxy aromatic precursors are either known compounds ormay be prepared by any convenient method known to those skilled inorganic synthesis. The precursors may generally be prepared byDiels-Alder synthesis either alone or together with other readilyapparent synthetic steps. The Diels-Alder synthesis is generally basedon readily available starting materials and their simpler Diels-Alderadducts. The following illustrative 1 3 synthesis sequence shows thepreparation of one preferred precursor:

dehydrogenation (Raney nickel) HaC- CH:

nooc- -coon The reaction of an appropriate dialkyl dicarboxy aromaticprecursor with nitrosyl halide or any one of its aforementionedalternatives, is the preferred method for the preparation of thebis(hydroxamoyl halide)-bis(carboxylic acids). lFOl' example,

01 CH: NOOl HON=O =NOH nooc O -coo11 1 4-bls (carbohydroxamoylchloride)-5, 8-dlcarboxynaphthalene nooc- 0 -OOOH 1, 4-d1rnethyl-5, 8dlcarboxynaphthalene Instead of the aromatic reactant used in the aboveillustration, one may use an aromatic reactant corresponding to thedesired aromatic bis(hydroxamoyl halide) -bis(carboxylic acids)described above. This preferred step in combination with the basicprocess of this invention, i.e., the reaction of the bis(hydroxamoylhalide)-bis(carboxylic acid) with an aromatic diarnine results in arelatively simple, easy, relatively inexpensive, overall process for thepreparation of polyamidoximes from readily available starting materials.These polyamidoximes may be converted to BBB type polymers by a ringclosure reaction.

The preferred process for the preparation of bis(hydroxamoyl halide)bis(carboxylic acids) may be conducted at temperatures of from about 10C. or lower to about 50 C. or higher. The reaction may be conducted atpressures in the range of an atmosphere or more, e.g.,

up to about 10 atmospheres, preferably from about one to aboutatmospheres. In view of the corrosive nature of some of the reactantsand products, such as nitrosyl halide, it is preferred to conduct thereaction in a reactor fabricated from a material which is inert underthe reaction conditions, for example, a glass-lined reactor or onefabricated from titanium or nickel.

To enable the reader to more easily visualize the steps of theinvention, the following schemata are set forth, using illustrativereactants. It will be readily apparent to the reader, however, that theother reactants mentioned throughout the specification and claims may beused in their stead.

14 PREPARATION OF AMIDOXIME POLYMER FROM BIS(I-IYDROXAMOYL CHLORIDE)-BIS(CARBOX- YLIC ACID) It is possible that a bis(hydroxamoylhalide)-bis(carboxylic acid) may decompose in the presence of certainacid-acceptors in accordance with the following illustrative reaction:

HON 0 HON H000 \COOH Hydroxamoyl chloride 0 a-- N50 GEN O-l-HCl HO0C- O-CO0H Nltrile oxide In order to inhibit or eliminate this side reaction,other alternative reactants may be used in place of this bis-(hydroxamoyl halide) in the reaction to form ami-doxime polymers, e.g.,the O-sulfonate derivatives, which may be formed in accordance with thefollowing illustrative schemes.

PREPARATION OF O-SULFONATES OF (BIS) HYDROXAMOYL CHLORIDES c1 or o- -o y2@ 011230201 HON O NOH on N HOOC/ 00011 P 2 m or :1 @-cmolsonC=NOSO2CHI-@ H000 0 00011 c1 c1 HON=23 OH K20 0:

(:1 n xoolsoN= s-@-o=nosolox HOOC O CO0H HOOC- Q PREPARATION 'OF BBBFROM IMIDAZOLE POLYMER The reaction above may be conducted at elevatedtemperature, e.g., temperatures up to about 390 C., preferably up toabout 300 C. More specific methods are given in examples I, II and III,which follow.

The following examples are illustrative of the invention:

EXAMPLE I A volume of 100 mls. of DMAc dried over Linde sieves waspurged with dry nitrogen. A weight of 3.71 grams (0.01 'mole) of1,4-bis(carbohydroxamoylchloride)-5,8- dicarboxy naphthalene isdissolved in the dry DMAc. To this solution are added 1.84 grams (0.01mole) of benzidine. While stirring at about 40 C., a weight of 2.52grams (0.2 mole) of melamine is added in small portions over the courseof two hours. Stirring is continued for another two hours, during whichthe reaction mixture thickens as melamine hydrochloride and thepolyamidoxime come out of solution.

The reaction mixture is added to cold water, and the polymer is filteredand Washed thoroughly with hot water, to remove melamine hydrochloride,and then with alcohol and ethyl ether.

The polyamidoxime is dissolved in 40 mls. of dry pyridine and thesolution cooled in an ice-bath. A weight of 3.81 grams (0.02 mole) oftoluene sulfonyl chloride dissolved in 20 mls. of benzene and 10 mls. ofpyridine chloride is added with stirring and cooling. The mixture isallowed to stand at C. overnight to effect ring closure of thepolyamidoxime to polynaphthimidazole.

The ring closure of the polynaphthimidazole to give BBB polymer can beeffected in a number of ways, the most convenient of which is to heat toreflux in DMAc or DMSO for 2 to 3 hours. Or, the polymer may be heatedto about 170 C. in conc. sulfuric acid or polyphosphoric acid for a fewhours. The BBB is separated by cooling the solution and precipitatingwith water, Washing and drying.

EXAMPLE II To a reaction flask equipped with stirrer, nitrogen bubblingtube and dropping funnel are added 100 mls. of

dry cyclohexanone. A slow nitrogen flow is started to drive air from thesystem before adding reactants. A weight of 3.71 grams (0.01 mole) of1,4-bis(carbohydroxamoyl chloride)-5,8-dicarboxy naphthalene is added. Aweight of 2.00 grams (0.01 mole) of oxydianiline is added in portionsover the course of one hour at room temperature. At this point, additionof melamine in small portions is begun and is continued for another twohours at room temperature, the total Weight of melamine added being 2.52grams (0.02 mole). The mixture thickens gradually over the next 10hours. The reaction mixture is added to water, and the polyamidoxime isfiltered, washed and dried. The polymer is dissolved in 30 mls. drypyridine, to which a cooled solution of 3.81 grams (0.02 mole) oftoluene sulfonyl chloride in 20 mls. benzene and 10 mls. pyridine isadded. After standing overnight at 0 to +5 C., the polynaphthimidazoleis isolated, washed and dried.

This polymer is now added to 50 mls. conc. sulfuric acid and thesolution heated to 170 for three hours. If desired, this solution may beused directly for spinning into a BBB fiber, or the polymer may beprecipitated, washed and dried as before.

EXAMPLE III A solution of 7.42 grams (0.02 mole) of1,4-(biscarbohydroxamoyl chloride)-5,8-dicarboxy naphthalene in 100 mls.dry N-methyl pyrrolidone is prepared, after purging the system with drynitrogen. To this solution, 3.96 grams (0.02 mole) of p,p'-diaminodiphenylmethane are added with stirring at 30-40 C. After about 7 hoursof stirring, the mixture is cooled to 5 C., and a cooled solution of7.62 grams (0.04 mole) of toluene sulfonyl chloride in 50 mls. of drypyridine is added. The mixture is placed in a refrigerator for 12 hoursand is then poured into water, filtered and washed with hot water,alcohol and ether.

The polynaphthimidazole is added to 100 mls. of DMAc containing 5% LiCland ring closure is effected by refluxing for about 3 hours. On cooling,the BBB type polymer is separated, washed and dried.

EXAMPLE IV Preparation of 1,4-bis(carbohydroxamoyl)-5,8- dicarboxynaphthalene A mixture of nitrosyl chloride and chlorine is generatedfrom concentrated nitric and hydrochloric acids:

The NOCl and C1 are passed into a vessel containing a solution1,4-dimethyl-5,8-dicarboxy naphthalene in carbon tetrachloride. A UVlamp irradiates the reaction mixture, maintained at 15 C., duringcontinuous introduction of gaseous NOCl and C1 The1,4-bis(carbohydroxamoyl)-5,8-dicarboxy naphthalene is largely insolublein the medium and is filtered off and recrystallized from chloroform.The unchanged dimethyl starting material plus by-products can beretreated for further conversion to product.

An alternate starting material (1,4-bischloromethyl-5,8- dicarboxynaphthalene) for the above reaction can be prepared as follows:Naphthalene g.), aqueous 40% formaldehyde (220 g.), and conc. HCl arerefluxed 16 hours while passing a stream of HCl gas through the mixture.Crude bis-chloromethyl naphthalene (19 g.) is largely the 1,4-derivativewhich is purified by recrystallization. l-chloromethyl naphthalene (43g.) is recycled to the next run. The 1,4-bischloromethyl derivative isoxidized to 1,4-dicarboxy naphthalene with alkaline permanganate.Repetition of the above chloromethylation procedure on 1,4 dicarboxynaphthalene gives crude 1,4- bischloromethyl-5,8-dicarboxy naphthalenewhich is purified and subjected to reaction with NOCl and C1 17 What isclaimed is: 1. A polyamidoxime polymer consisting essentially ofrecurring units of the formula:

LHOIi H006 \COOH NOH wherein R is a tetravalent carbocyclic aromaticradical or an aromatic radical having a divalent bridge group selectedfrom divalent radicals having the following formula:

joining two carbocyclic aromatic radicals which radicals have the totalof four valence positions, none of which are present on said bridgegroup and wherein said valences are so positioned that each carboximegroup and the carboxy group closest to it are attached together througha chain of two or three carbon atoms of the R' radical; and Y is a 4- 1os, u a

2. The polyamidoximes of claim 1 wherein R is a tetravalent aromaticradical containing up to about 18 carbon atoms.

3. The polyamidoximes of claim 1 wherein R contains 10 carbon atoms.

4. The polyamidoximes of claim 1 wherein Y is either 5. Thepolyamidoximes of claim 1 consisting essentially of recurring units ofthe formula:

OH gl we; I 3

COOH

6. An imidazole polymer consisting essentially of recurring units of theformula:

C N7Y N;C COOH\N N/ I wherein R is a tetravalent carbocyclic aromaticradical or an aromatic radical having a divalent bridge group selectedfrom divalent radicals having the following formula:

References Cited UNITED STATES PATENTS 3/ 1971 Pruckmayr 260-47 12/1968Paufler 260-47 6/1970 Funer 260-47 3,532,673 10/ 1970 Bell, Jr. et al26078 3,549,594 12/1970 Twilley et al 260-47 LESTER L. LEE, PrimaryExaminer US. Cl. X.R.

260-302, 30.6 R, 308 DS, 31.2 N, 32 A, 32.6 N, 32.8 N, 33.2 R, 47 CP,49, 63 R, 448.2 B, 448.2 N, 453 R, 456 A, 566 D CH; Cam CIH8 Sii, -Si-,or Si CH: :30 0E:

